At present, various hydraulic valves driven by motors are widespread. The drive mode is divided into a dual-motor drive mode and a single-motor drive mode.
Current various hydraulic valves driven by two motors generally have complex structures. Compared with controlling a single valve core by a single motor, driving double valve cores to work by two motors is more difficult to achieve an equivalent control effect. For example, Chinese patent with Application Number 200510082720.8 discloses a “Rotary Digital Direction Flow Valve Without Shaft Extension”, which includes a main valve core and a slave valve core. The valve core has teeth arranged on the outer circumference thereof and is coupled with a motor via a gear, thereby avoiding defects such as slipping. However, the teeth processing on the outer circumference of the valve core increases the difficulty of manufacturing and the structure is more complex. Furthermore, the coupling with the motor via the gear also reduces the control precision. Chinese patent with publication number CN88200510U discloses a “Rotary Hydraulic Servo Valve”, which includes two valve cores that are rotated relative to each other and are driven to rotate by two motors respectively. The two valve cores are not symmetrical. One valve core has three holes while the other valve core has one oil return hole, thus the two valve cores are not stressed evenly. Moreover, an oil return hole is defined on an end cap, thus the end cap is affected by liquid pressure and the structure is instable. Chinese patent with publication number CN103089732B discloses a “Double-Valve-Core Rotary Type Direction Throttle Valve Driven By Two Motors”, wherein channels A and B form one valve core and channels P and T form the other valve core. The two valve cores are driven by respective motors. If to realize individual channel control, two drive motors are needed to coordinate and control respectively. Since the valve structure determines that the control precision must be higher than a difference between a diameter of the P, T hole channel of the valve core P, T and a diameter of an orifice sealing pin of the P, T in an annular groove C of the valve core A, B, the two drive motors must have respective position feedbacks and the precision must be higher than the control precision. Chinese patent with publication number CN102889254A discloses a “Dual-Drive Servo Valve And Control Method Thereof”, wherein one motor at one end drives a valve core through a lead screw to convert a rotational motion into a linear motion, thereby driving the valve core to slide inside a valve body. The valve body of the valve core has a structure similar to a universal solenoid valve. A nut at the other end is connected to the other motor. The motor at the nut end controls the fine tuning of the opening of the valve hole. The regulation precision is restricted by mechanical processing, screw thread range and precision. Since the two motors at the two ends are controlled simultaneously, both processing difficulty and control difficulty are increased.
In the prior art, direction control hydraulic valves adopting spool valve structures can realize control in direction only, and pressure or flow hydraulic valves can realize control of pressure or flow only. One same valve body cannot realize multiple different control modes and have a single function.
To sum up, for the single-valve-core hydraulic valves in the prior art, one cannot realize multipurpose use and cannot achieve multiple control modes by directly operating the valve core.
The information disclosed in the above background is merely to improve the understanding of the general background of the present disclosure, and cannot be viewed as recognizing or implying in any form that the information already becomes the available technology commonly known by the ordinary skill in the art.